Normally, to vulcanize a raw tire, a mold (a metal mold) having its inside filled with a raw tire is heated by a heating medium, and a heating medium including high-temperature, high-heat-capacity steam and a pressurizing medium including noncondensable gas such as inert gas or nitrogen gas are supplied to an internal space of the raw tire, thereby heating the raw tire from outside and inside (for example, refer to Patent Document 1). Note that the heating medium and the pressurizing medium may be hereinafter collectively referred to as a vulcanization medium.
In general, as shown in FIG. 15, a vulcanizing system 300 includes a boiler 102 which is located outside a building 104, a plurality of (for example, twenty to hundred) vulcanizers 101 which are placed in the building 104, and a piping 103 which connects the boiler 102 and the vulcanizers 101. In the vulcanizing system 300, steam generated by the boiler 102 is supplied to each vulcanizer 101. In this case, steam is generally supplied from one boiler 102 to every vulcanizer 101 in the building 104. Since this boiler 102 is large, it cannot be placed near the vulcanizers 101, and therefore the total length of the piping 103 between each vulcanizer 101 and the boiler 102 is as long as several hundred meters.
In the structure as described above, however, when steam is supplied from the boiler 102 to via the piping 103 to each vulcanizer 101, a considerable amount of heat of steam is lost by heat dissipation from the piping 103, thereby causing a large energy loss. According to studies by the inventors, a trial calculation indicates that approximately ⅓ of the amount of heat introduced from the boiler 102 is dissipated.
To prevent this problem, Patent Document 2 suggests that a heat supply means is separately provided for each vulcanizer, the heat supply means capable of heating a raw tire by heating a heating medium and supplying an amount of heat to a bladder via the heated heating medium. Patent Document 2 descries a heat supply means having a circular route and a temperature control apparatus. The circular route takes out a heating medium in the bladder outside the vulcanizers and returns the taken-out heating medium to the inside the bladder. Outside the vulcanizers, the temperature control apparatus controls supply power to an electric heater for heating the heating medium circulated in the circular route.